At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica

  • Piotr Jadwiszczak University of Bialystok
Keywords: Antarctic Peninsula, La Meseta Formation, Palaeogene, early Sphenisciformes, cervicodorsal vertebra

Abstract

The spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series, comprising reinterpreted known material and a new specimen from the Eocene of Seymour Island (Antarctic Peninsula), were investigated and contrasted with those of modern penguins and some fossil bones. The new specimen is smaller than the counterpart elements in recent king penguins, whereas the second series belonged to a large-bodied penguin from the genus Palaeeudyptes. It had been assigned by earlier researchers to P. gunnari (a species of “giant” penguins) and a Bayesian analysis—a Bayes factor approach based on size of an associated tarsometatarsus—strongly supported such an assignment. Morphological and functional studies revealed that mobility within the aforementioned segment probably did not differ substantially between extant and studied fossil penguins. There were, however, intriguing morphological differences between the smaller fossil specimen and the comparative material related to the condition of the lateral excavation in the first cervicodorsal vertebra and the extremely small size of the intervertebral foramen located just prior to the first “true” thoracic vertebra. The former feature could have resulted from discrepancy in severity of external pneumatization. Both fossils provided valuable insights into the morphology and functioning of the axial skeleton in early penguins.

Keywords: Antarctic Peninsula; La Meseta Formation; Palaeogene; early Sphenisciformes; cervicodorsal vertebrae.

(Published: 20 November 2014)

Citation: Polar Research 2014, 33, 23861, http://dx.doi.org/10.3402/polar.v33.23861

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Author Biography

Piotr Jadwiszczak, University of Bialystok

Institute of Biology, Faculty of Biology and Chemistry

researcher and academic teacher (with Ph.D.)

 

Published
2014-11-20
How to Cite
Jadwiszczak, P. (2014). At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica. Polar Research, 33. https://doi.org/10.3402/polar.v33.23861
Section
Research/review articles